It is generally known in the automotive industry to transport rough cast engine blocks in a stacked relationship comprised of multiple layers of engine blocks divided by horizontally disposed dunnage trays. More specifically, rough cast internal combustion engine blocks are often stacked on plastic dunnage trays adapted to support four engine blocks in, for example, a 2.times.2 arrangement. In this manner, four engine blocks are positioned atop a bottom dunnage tray. An intermediate dunnage tray is then placed atop the bottom four layered engine blocks, and an additional layer of four engine blocks is then placed atop the intermediate dunnage. In this fashion, layers of engine blocks and dunnage trays can be placed one atop the other in a multiple layered fashion such that stacks of up to three or four layers of engines can be achieved. It is known that the amount of engines and dunnage trays stacked depends upon the structural capabilities of the dunnage trays and the individual weight of each internal combustion engine block.
In this manner, it is known to transport these rough cast engine blocks from the initial manufacturing casting location to a machining location. The rough cast engine blocks are often subjected to numerous machining operations, ranging from rough machining or grinding to intermediate machining, and finally to finishing or microfinishing. The stacks of engine blocks are received at the machining location and must be unloaded from the stacked position and loaded one by one onto the various machining operations loading stations.
Currently, a human operator must manually remove the top dunnage tray which is used for protection of the top layer of engine blocks. The dunnage tray is often removed and placed in a position where the rest of the intermediate, and lower dunnage trays can be stacked for reuse or recycling. After the top dunnage tray is removed, the operator manually affixes a tong-like device or other like device which is capable of adequately gripping the engine block. The operator then initiates a manual operation where the engine block is lifted off the dunnage tray. The operator then must manually manipulate the raised engine block which weighs anywhere from 100 to 300 pounds to the loading station of the machining operation and disengage the tong-like gripper from the block.
In this manner, the operator repeats the procedure for each particular engine block of each layer and then must remove the intermediate dunnage trays until the entire stack has been loaded onto the machining operation line. Additionally, the operator stacks the dunnage trays in some sort of organized fashion.
After the block is cast, and after the initial machining, the block is shipped to a manufacturing location. To facilitate this, the blocks are stacked on their respective dunnage for shipping. When the blocks are received at the machining location, they must again be unloaded.
It is thus desirable to provide an automated apparatus or method for loading and unloading both stacked engine blocks and the required dunnage needed for the stacked fashion. This automated system is desirable for providing loading and unloading of the engine blocks quickly and efficiently. It is known that manual loading and unloading is time-consuming, and each individual operator must affix tong-like mechanisms to each engine block which is often difficult and time-consuming. Further, movement of the engine block in a lateral fashion after the tong mechanisms have been affixed must be effectuated in a reasonably calculated and determined fashion due to the weight of each individual engine block and the difficulty in placing the engine block in the exact spot at each individual loading station.
U.S. Pat. No. 4,887,341 to Sakimori et al. discloses a robot for properly registering a cylinder head to an engine block. The cylinder head is set on the engine block while inserting protruding coupling bolts into bolt engaging bores in the engine block, thereby temporarily holding the cylinder head on the engine block.
U.S. Pat. No. 4,368,913 to Brockman et al. discloses a robot gripping device for gripping workpieces having opposite contoured faces. The gripping jaws include double parallel linkages including a coupler link at one end of the linkage which carries the clamping jaw and a flap interconnecting two parallel crank arms.